Authority is an ambiguous word. It may indicate knowledge of truth, and it may indicate a rightful power to command obedience. The authoritativeness attributed to the moral law has often reference to both kinds of authority. The moral lawgiver lays down his rules in order that they should be obeyed, and they are authoritative in so far as they have to be obeyed. But he is also believed to know what is right and wrong, and his commands are regarded as expressions of moral truths. As we have seen, however, this latter kind of authority involves a false assumption as to the nature of the moral predicates, and it cannot be justly inferred from the power to command. Again, if the notion of an external lawgiver be put aside, the moral law does not generally seem to possess supreme authority in either sense of the word. It does not command obedience in any exceptional degree; few laws are broken more frequently. Nor can the regard for it be called the mainspring of action; it is only one spring out of many, and variable like all others. In some instances it is the ruling power in a man's life, in others it is a voice calling in the desert; and the majority of people seem to be more afraid of the blame or ridicule of their fellowmen, or of the penalties with which the law threatens them, than of "the vicegerents of God" in their own hearts. That mankind prefer the possession of virtue to all other enjoyments, and look upon vice as worse than any other misery,[20] is unfortunately an imagination of some moralists who confound men as they are with men as they ought to be. [Footnote 20: _Idem_, _Inquiry into the Original of our Ideas of Beauty and Virtue_, p. 248.]